With continuing improvement in semiconductor based solid-state light emitting devices, Edison's incandescent light bulbs, which typically have less than 30% of light efficiency, will soon be replaced with energy-efficient semiconductor based solid-state light emitting devices such as light-emitting diodes (“LEDs”). A conventional LED, for example, is small, energy efficiency, and long lifespan. Various commercial applications relating to solid-state lightings, such as homes, buildings, street lightings, traffic lights, and electronic billboards, have already placed in service.
An LED device typically contains a biased p-n junction which is capable of emitting narrow-spectrum light or electroluminescence. Amount of emitted light and/or color of light usually depends on the composition of optical material(s) used in the LED device. The efficiency of LED device as well as color variations associated with the visible light are partially dependent on the type of optical material(s) or optics used.
A conventional optical material or optics is ploy methyl methacrylate (“PMMA”) which is commonly used in the LED field. Although PMMA provides efficient light passage as well as versatile moldability, a drawback associated with conventional PMMA material is that it possesses a relatively low operating and/or melting temperature. With increasing power and optical flux generated by new LEDs or LED arrays, the conventional PMMA material becomes less desirable optical material for high-powered LED devices partially because of its relatively low operating temperature and/or heat tolerance.